I am attempting to set up a communication between Labview and Microsoft SQL Server, on two separate devices, in order to send and receive information about the database from both labview to SQL Server and SQL Server to labview. However, when I reach the "Data Link Properties" menu, I get the same "unable to log in" error upon attempting to log into the server. The server name comes up, however, an error occurs once I move on to select the database on that server. Is there any solution or tutorial to this problem that can allow me to successfully communicate back and forth from labview and smss on separate devices?
I've opened up various ports to allow a connection, even disabled the firewalls on both devices. The devices are connected via an Ethernet cable and I AM able to ping the devices to each other. However, in regards to being unable to log into the server in ssms, I have created new users, adjusted the login properties, tried changing permissions, but anything I try doesn't seem to solve my issue.
Can't really help much without seeing the error or some of the code of what you are trying to do.
That being said, if you go to the menu and select Help>Find Examples... and search for database, you should see a bunch of different things related to database connections. You may find the Database Connection.vi one helpful.
More info on the Database Connectivity Toolkit in LabVIEW can be found here
I see there can be one of the 2 issues
1) Inbound/Outbound port rules not set, Remote connection to server is not allowed.
2) If the server has multiple instances then you need to provide full host name of the instance you are trying to connect.
*Please refer to the below link to configure firewall rules.
https://learn.microsoft.com/en-us/sql/sql-server/install/configure-the-windows-firewall-to-allow-sql-server-access?view=sql-server-2017
Related
I'm working on logs. I want to reproduce a log in which the application fails to connect to the server.
Currently the commands I'm using are
db2 force applications all
This closes all the connections and then one by one I deactivate each database using
db2 deactivate db "database_name"
What happens is that it temporary blocks the connections and after a minute my application is able to create the connection again, due to which I am not able to regenerate the log. Any Ideas how can I do this?
What you are looking for is QUIESCE.
By default users can connect to a database. It becomes active and internal in-memory data structures are initialized. When the last connection closes, the database becomes inactive. Activating a database puts and leaves them initialized and "ready to use".
Quiescing the database puts them into an administrative state. Regular users cannot connect. You can quiesce a single database or the entire instance. See the docs for some options to manage access to quiesced instances. The following forces all users off the current database and keeps them away:
db2 quiesce db immediate
If you want to produce a connection error for an app, there are other options. Have you ever tried to connect to a non-estisting port, Db2 not listening on it? Or revoke connect privilege for that user trying to connect.
There are several testing strategies that can be used, they involve disrupting the network connection between client and server:
Alter the IP routing table on the client to route the DB2 server address to a non-existent subnet
Use the connection via a proxy software that can be turned off, there is a special proxy ToxiProxy, which was designed for the purpose of testing network disruptions
Pull the Ethernet cable from the client machine, observe then plug it back in (I've done this)
This has the advantage of not disabling the DB2 server for other testing in progress.
(I am a sql noob and I just can not figure this out on my own)
For some time now I have been trying to establish a connection to a SQL database in codename one but to no avail. First I tried connecting to a MariaDB database from one.com. All that's needed for the connection is
Database db = Display.getInstance().openOrCreate("databaseName");
if I am not mistaken, but I am guessing this implies that I have somehow already established a connection to the database. This is not the case however so it creates a new .sql file, right? I can recall that you can connect to a database in the services tab in Netbeans. I chose the MySQL(Connector/ J Driver) which should work with MariaDB, or should it? I entered all my data and i says that it can not establish connection to the database.
the error i get
So I thought I might as well try using localhost. I used XAMPP to host a database and connected in the netbeans services tab.
connected?
Now testing was needed to see if this works. I started the SQL journey with this https://www.codenameone.com/manual/files-storage-networking.html#_sql and integrated the part after "You can probably integrate this code into your app as a debugging tool". I changed database name to "mybase" (it's existance can be confirmed in picture 2). Ran the app, opened the dialog, entered "select ID from customers" and got: java.sql.SQLException: [SQLITE_ERROR] SQL error or missing database (no such table: customers) It does not get past the first call to "executeQuery". The customers table definitely exists so what am I missing to establish connection?
I really need instructions to connect to the localhost database and ideally also to the one hosted by my webhost provider.
Thanks,
Jona
The Database class is to access the SQLite DB on the mobile device. To connect to external databases, you'd have to do something different, such as a ConnectionRequest or Socket I think.
I have hosted my WebApp on server 1 and my database on server 2
But I'm getting following error
Communication with the underlying transaction manager has failed.
I googled and found a post which mentioned that it is the issue of DTC(Distributed Transaction)
I enabled DTC on server2(DB server) and made an exception of it in Firewall.
But still same error.
Here is the full stack trace
Message: System.Transactions.TransactionManagerCommunicationException: Communication with the underlying transaction manager has failed. ---> System.Runtime.InteropServices.COMException: The MSDTC transaction manager was unable to pull the transaction from the source transaction manager due to communication problems. Possible causes are: a firewall is present and it doesn't have an exception for the MSDTC process, the two machines cannot find each other by their NetBIOS names, or the support for network transactions is not enabled for one of the two transaction managers. (Exception from HRESULT: 0x8004D02B)
at System.Transactions.Oletx.IDtcProxyShimFactory.ReceiveTransaction(UInt32 propgationTokenSize, Byte[] propgationToken, IntPtr managedIdentifier, Guid& transactionIdentifier, OletxTransactionIsolationLevel& isolationLevel, ITransactionShim& transactionShim)
at System.Transactions.TransactionInterop.GetOletxTransactionFromTransmitterPropigationToken(Byte[] propagationToken)
Kindly advice
We had the exact same situation, and more than once. Each time, it was one of the following:
The IP address in the DNS for the server is outdated (as said in error message: "two machines cannot find each other by their NetBIOS names"). You can check if this is the case by trying ping servername from one server to another in the command prompt. If the ping by name fails and ping by IP succeeds (or ping by name returns the wrong IP), than you should talk to the System Admins to take a look at DNS/DHCP.
The servers are created as an image of preconfigured server (for example, if you are working with virtual machines, and instead of doing a fresh install for each of the servers, you simply clone the image). This is a problem because DTC has an internal "Identifier" - and in case of image cloning both your installations now have same DTC ID, and won't be able to communicate with each other. The solution is to simply uninstall and install the DTC again.
Hope it helps.
Things to check:
Have you done this configuration on both servers?
Are both servers members of the same domain?
Have you checked the event log?
I had the same problem while connecting to a remote SQl Server.
The solution in my case was to add "enlist=false" to the connection string.
I was missing quite a lot of things:
No authentication (as DB server and APP server and not within same AD domain)
Rule to Windows Firewall enabling msdtc.exe
Rule to firewall between DMZ and internal zone TCP 135,1024-65535 in both directions. The link tell you how to restrict the firewall policy to few ports only.
short / long server names to hosts or a shared DNS server. Eg. 192.168.1.1 app1 as well as 192.168.1.1 app1.domain.local
On the other hand based on this link my setup doesn't require:
Allow Remote Clients
Allow Remote Administration
Enable XA Transactions (required prior Windows Server 2003 SP1)
Solved after adding remote IP\machine name to files on server:
hosts, lmhosts
in folder
C:\Windows\System32\drivers\etc
One of our servers displayed this error after the Virtual Machine (VM) controlling our Domain Controller froze. Several related communication problems also started to pop up (like failed password resets). Resetting the frozen VM fixed the issue.
Lots of helpful answers already given.
One problem for me was the presence of invalid (cyrillic) characters in the computer name.
And there is also a way to validate the connection between two servers (or between a server and a computer) using a small tool from Microsoft called DTCPing.
When I link the Microsoft Access to SQL Server locally, everything works. The second I go to a computer that is on the network, I am not able to open the form I created on the Access database.
I found out that if I open the link, I will get an error. If I choose where the DB through configurations in Access, I get the error again. If I try this a third time, it connects to the database and it is fully linked--I am able to type data into Access and it will store it in the SQL Server database as well.
My question is: How do I get it to connect to the server on the first try? I have to hit "connect" three times which takes about 5 minutes to log in. That isn't very efficient when the people using this program nothing about computers.
Linking Access to SQL Server uses ODBC. Make sure your ODBC settings are correct.
I'm trying to set up mirroring between two sql 2008 databases on different servers in my internal network, as a test run before doing the same thing with two live servers in different locations.
When I actually try and switch the mirroring on the target DB (with
ALTER DATABASE testdb SET PARTNER = N'TCP://myNetworkAddress:5022') I'm getting an error telling me that the server network address can not be reached or does not exist. A little research suggests this is a fairly unhelpful message that pops up due to a number of possible causes, some of which are not directly related to the server existing or otherwise.
So far I've checked and tried the following to solve this problem:
On the target server, I've verified that in SQL Configuration Manager that "Protocols for SQLEXPRESS" (my local installation is labelled SQLEXPRESS for some reason, even though querying SERVERPROPERTY('Edition') reveals that it's 64-bit Enterprise), and Client Protocols for SQL Native Client 10 all have TCP/IP enabled
I'm using a utility program called CurrPorts to verify that there is a TCP/IP port with the same number specified by the mirroring setup (5022) is open and listening on my machine. Netstat verifies that both machines are listening on this port.
I've run SELECT type_desc, port FROM sys.tcp_endpoints; and
SELECT state_desc, role FROM sys.database_mirroring_endpoints to ensure that everything is set up as it should be. The only thing that confused me was the "role" returns 1 .. not entirely sure what that means.
I've tried to prepare the DB correctly. I've taken backups of the database and the log file from the master DB and restored them on the target database with NORESTORE. I've tried turning mirroring on both while leaving them in the NORESTORE state and running an empty RESTORE ... neither seems to make much difference. Just as a test I also tried to mirror an inactive, nearly empty database that I created but that didn't work either.
I've verified that neither server is behind a firewall (they're both on the same network, although on different machines)
I've no idea where to turn next. I've seen these two troubleshooting help pages:
http://msdn.microsoft.com/en-us/library/ms189127.aspx
http://msdn.microsoft.com/en-us/library/aa337361.aspx
And as far as I can tell I've run through all the points to no avail.
One other thing I'm unsure of is the service accounts box in the wizard. For both databases I've been putting in our high-level access account name which should have full admin permissions on the database - I assumed this was the right thing to do.
I'm not sure where to turn next to try and troubleshoot this problem. Suggestions gratefully received.
Cheers,
Matt
I think that SQL Express can only act as a witness server with this SQL feature, you might get better mileage on ServerFault though.
Mike.
Your network settings might be OK. We got quite non-informative error messages in MS SQL - the problem might be an authorization issue and the server still will be saying "network address can not be reached".
By the way, how the authentication is performed? A MSSQL service (on server1) itself must be runned as a valid db user (on server2, and vice versa) in order to make the mirroring work.